The invention relates to a device for manufacturing a tube coupling of two tube ends, and in particular a tube coupling which at least comprises a basic body enclosing the tube end, and a press means enclosing the basic body wherein the basic body is radially urged into the surface of the tube by axially shifting the press means.
Pipe connections using this principle are known from the patent specifications U.S. Pat. Nos. 3,827,727, 3,893,720, 4,026,006, 4,061,367, 4,482,174 and 5,110,163.
The disadvantage of these pipe connections is in that they are functionally restricted in use regarding the size of the tube diameter, claims of quality on the tube to be connected, and the amount of pressure of the medium. Moreover, the constructional design of the displacing potentials formed in these tube couplings provides in addition to the intended radial crowding being absolutely necessary to obtain a pressure sealed connection, an axial crowding which does not contribute to the pressure sealed connection but influences the forces of pressure to be applied from the outside such that the forces of pressure exceed the dimension required for the radial crowding. Thus, from the start follows an oversizing of both the press tool and single elements of the tube coupling.
The invention is based upon the object to provide a pressure sealed pipe connection by axially pressing which ensures highest universality regarding the requirements of quality of the tubes to be connected.
Another object of the invention is in that to make a sealed connection in the high pressure range as well by the use of normal commercially available tubes, e.g. welded tubes made of most different materials, and the thus permissible tolerances regarding the mechanical properties and length related dimensions.
Further, it is an object of the invention to minimize the forces required for axially pressing on the press elements, and thus the force to be applied for penetrating into the tube surface at maximum penetrating depth.
These objects will be solved by a device according to the features of the first claim.
The device for manufacturing a pressure sealed tube coupling having at least one tube end comprises a sleeve shaped, rotationally symmetrical basic body wherein the basic body at least includes one substantially cylindrical interior space provided with teeth means for receiving the tube end, and the teeth means are radially displaced into the surface of the tube end received by the interior space by means of press means acting upon the outer surface of the basic body.
The basic body comprises a hollow cylinder shaped coupling sleeve having a wall thickness substantially remaining the same wherein at least two radially surrounding indentations are located on the inside of the coupling sleeve which are spaced to one another and recessed in comparison with the inner diameter of the coupling sleeve. On the outside of the coupling sleeve are formed radially surrounding flat locating features opposite the respective indentation which have a width corresponding to the width of the indentation. For it, a pressure ring concentrically slidable over the coupling sleeve is provided to cover the coupling sleeve in almost its total length wherein the pressure ring has radially surrounding projecting parts corresponding to the locating features on its inside, and an increasing cone shaped enlargement directed from each end of the pressure ring towards its centre, on its outside.
A press ring concentrically enclosing the pressure ring is associated to the pressure ring on each side, wherein each press ring on its inside has a cone shaped enlargement corresponding to the cone shaped enlargement of the pressure ring such that a radial displacement of the indentations into the surface of the tube received by the coupling sleeve by means of the projecting parts and the locating features corresponding to the projecting parts occurs during the axial shift of the press rings against each other from a spaced initial position into an almost final position without any distance.
Further features of the invention are cited in the dependent claims.
The invention will be explained in more detail according to an embodiment shown the associated drawings.